Collapsible box



FIG. 1 is a top plan view showing my new design for a collapsible box in an unfolded, flat state, and the lines shown in dashed lines are fold lines,

FIG. 2 is a front and left side perspective view thereof, in a partially folded position and the lines shown in dashed lines are fold lines,

FIG. 3 is a top, sides and rear perspective view thereof, the lines shown in dashed lines are fold lines,

FIG. 4 is a right side and rear perspective view thereof; and,

FIG. 5 is a bottom view thereof, the lines shown in dashed lines are fold lines.

The dashed lines in the drawings depict fold lines and form part of the claimed design. 

CLAIM The ornamental design for a collapsible box, as shown and described. 